Blow-off valve.



A. H. JOHNSON.

BLOW-OFF VALVE.

. APPUCATION FILED MAYS. 1915.

Fly. L 2'.

Q Hozne 1 Patented Sept. 4, 1917.

ALBERT H. JOHNSON, 0F GLEN 'S FALLS, NEW YORK.

BLOW-OFF VALVE.

To. all whom it may concern:

Be it known that I, ALLBERT H. JOHNSON, a citizen of the United States,residing at Glens Falls, in the county of Warren and State of New York,have invented certain new and useful Improvements in Blow-Off Valves, ofwhich the following is a specification.

This invention relates to a safetyor blowoff valve adapted to be used inconjunction with a boiler or other container for fluids under pressureand contemplates as its principal object the provision of a valve whichshall offer a predetermined resistance to the action of the pressurefluid and which will permit such fluid to escape after such resistanceis overcome.

A more specific object, but of equal importance with the foregoing is toprovide a hollovx valve stem which is anchored to the boiler or othercontainer and which carries a slidable valve head or casing throughwhich a pressure fluid from the container may escape to the outeratmosphere, and to employ in conjunction with such valve casing springmeans offering a predetermined resistance to the escape of the pressurefluid.

The above and additional objects which will become apparent as thisexplanatory de scription proceeds, are accomplished by such means as areillustrated in the accompanying drawings, described in the followingspecification and then more particularly pointed out in the claim whichis appended hereto and forms a part of this application.

With reference to the drawings, wherein there is illustrated thepreferred embodiment of this invention as it is reduced to practice, andthroughout the several views of which like characters of referencedesignate similar parts:

Figure 1 is a vertical sectional view taken through the valve of thisinvention, as anchored to a boiler and before the resistance of thespring has been overcome,

Fig. 2 is a similar view, showing the relation of the parts whenassuming that position where the fluid of pressure may escape, and

Fig. 3 is a central horizontal section taken Specification 'of LettersPatent.

Patented Sept. d, 1917.

Application filed May 6, 1915. Serial No. 26,376.

of which carries the spacing disk 9 that forms a pistonand whichcontactswith the inner surface of the cylindrical valve casing 10 formaintaining the stem 8 in alinement therewith.

The casing 10 is provided with the integral closed top 11 and is adaptedto have a bottom cap 12 threadingly received upon its lower extremity,such bottom being apertured to slidably receive the stem 8. Packingmeans 13 is interposed between this bottom cap and a retaining plate 14:which is also apertured to slidably accommodate the valve stem, beingthreadingly retained in position by the valve casing 10. Suitableapertures 15 are formed in the valve casing walls to establishcommunication therebetween and the external atmosphere, such aperturesbeing of any desired size and number and being positioned atsubstantially the center of the valve. A. contractile coiled spring 16surrounds the body of the stem 8 and has its ends respectively securedWithin the cap 13 and anchored to the plate 6 as denoted by the numeralsl7 and 18. This spring is calibrated to withstand a desired pressure andwill, of course, vary with different installations of the valve of thisin vention.

In operation, it will be seen that the spring 16 normally holds thecasing top 11 in contact with the disk 9 so that no escape is permittedfor the fluids of pressure. Should however the pressure in the boiler 5rise beyond that pressure for which the spring 16 has been calibratedthe upward force of the confined fluid against the casing top 11 willovercome the spring resistance and force the valve casing bodily upwarduntil the apertures 15 are uncovered by passage of the disk 9. Theseapertures will offer an avenue of escape for the fluid and the latterwill continue to pass from the boiler 5 outwardly through such aperturesuntil the pressure, within. the boiler is so lowered as to permit thespring 16 to again draw the valve casing downwardly about the stem 8into the position illustrated in Fig. 1. When employing the blow-01fvalve of this invention as a damper regulator, a function for which itis also eminently fitted, the apertures 15 are dispensed with inbalancing the pressure between the spring 16 and the steam within thevalve casing.

It will be apparent that in the above is disclosed an embodiment of thisinvention capable of attaining the previously presented objects thereof,so that this invention may therefore be claimed as possessingtheadvantages and desirability set forth in such objects.

What is claimed is:

In a blow-off valve, a hollow stem connected at one end to a containerfor fluids under pressure, a piston disk screwed on the other end ofsaid stem, a cylindrical casing having a removable head sliding on saidstem and having fluid-tight connection therewith, said casing havingfluid-tight connection with said piston disk, outlet apertures beingformed in the casing a predetermined distance below its upper closedend, and 21 Copies of this patent may be obtained for calibratedcontractile spring surrounding said stern and connected at one end tosaid casing and at its'other end to the container and normally holdingsaid casing downwardly with its piston disk, in contact with its closedupper end but yielding under pressure within the container to allow thefluid to escape through the hollow stem and apertures. y

In testimony whereof I afiix my'sig' ature in 'presenceof two witnesses.

ALBERT H. JOHNSON.

Witnesses I THos. E. HILL,

S; F. HIGLEY.

five cents eachflay addressingthe Commissioner of-Patents,Washingtomhfl. l .7

